Combine the Blue cheese and the cream cheese in a mixer with a paddle and mix well, there should be very few lumps.,Refrigerate for 1 hour.,______,Store on a sheet pan lined with parchment paper.,Chill for at least 1 hour to overnight.,Pule the pistachios in a food processor or chop *finely*.,Roll the grapes in the nut powder and shape with the palms of your hands.,This can be done up to 1 hour before serving.,Do not refrigerate once the grapes have been rolled.